Duplication of the left anterior descending artery (LAD) is a rare anomaly, which was classified into four types by Spindola-Franco et al. in 1983.[1] It has short LAD, which ends its course before the cardiac apex as a proximal septal while the long LAD has a variable course which deviates either to the left or right ventricular side or has an intramyocardial course or can originate from right coronary artery (RCA) which gives rise to diagonal branches.

Coronary angiography (CAG) revealed an early division of the shorter proximal segment of the LAD into two branches. A branch, which had a short course, gave rise to the proximal septal branches and then terminated high into the anterior interventricular sulcus (AIS). Another branch with a longer course descended on the LV side and gave rise to diagonal branches. The long LAD reentered into the distal AIS as a small caliber vessel, which also terminated before the LV apex. The proximal segments of the large LAD (culprit lesion) and short LAD (small caliber) and 2nd obtuse marginal (OM2) arteries had significant stenoses [[Figure 1]a and Video 1]. RCA was normal with longer posterior descending artery, which curved around the cardiac apex to enter into the distal AIS [[Figure 1]b, [Figure 1]c and Video 2]. The patient underwent percutaneous transluminal angioplasty using drug-eluting stents to both proximal segments of the short LAD and OM2.

Figure 1: Conventional coronary angiography (pre-angioplasty) and reconstructed volume-rendered images obtained from the coronary computed tomography angiography (post-angioplasty) demonstrating the type 9 dual left anterior descending artery. The division of the proximal segment of left anterior descending artery into two branches, one with shorter course ran in the proximal anterior interventricular sulcus giving rise to septal branches and another branch with longer course descended on the left ventricular side, giving rise to diagonal branches (solid black arrows in a, e, and f) and reentered and terminated in the distal anterior interventricular sulcus as a small caliber vessel above the left ventricular apex (dashed white arrows in a and f). The right coronary artery was dominant vessel (b) with a long course of the posterior descending artery, which turned around the left ventricular apex to enter into the distal anterior interventricular sulcus (solid white arrows in c and d). There were three vessels supplying the anterior interventricular sulcus, hence called as triple left anterior descending artery. The proximal segment of longer left anterior descending artery and mid-segment of 2nd obtuse marginal artery has patent stents in situ as shown in c, d, and f. Also there was de novo lesion at the proximal edge of the stent of the proximal segment of longer left anterior descending artery (Asterisk in f)

Computed tomography angiogram at 6 months in view of recurrence of symptoms confirmed our initial angiographic findings with patent stents. In addition, there was significant stenosis of the proximal segment of LAD [Figure 1]d, [Figure 1]e, [Figure 1]f. We opted for optimal medical management, as stress echo did not demonstrate any inducible ischemia.

Discussion

Spindola-Franco et al. in 1983 described four types of dual LAD systems (1). Since then, the classification of dual LAD has been expanding with a few case reports describing types 5 and 6. Bozlar et al. in their series illustrated the nine types of dual LAD.[2] They added three newer types to the existing classification as types 7, 8, and 9 of dual LAD. Type 9 dual LAD as described by Bozlar et al. was similar to our case as described earlier. They described it as “triple LAD anomaly” as the three varieties of vessels entering into the IVS. The clinical significance of this type of dual LAD system is not known exactly, but we hypothesize that it may reduce the magnitude of ischemia/infarction due to early division, which adds to the survival advantage of the patient.

Conclusion

We report the second case of type 9 dual LAD after an index case by Bozlar et al. The classification of the dual LAD is confusing and evolving further, which needs modification for better understanding and its clinical utility.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.